(And yes, iOS. That's the new name Apple has licensed from trademark holders Cisco to represent the iPhone, iPad, and iPod touch -- and maybe soon Apple TV and who knows what else -- family.)

Apple promises 7 "tent-pole" features and 100+ new user features overall, along with 1500 major new APIs for developers. We're going to walk through the ones that matter most. As with previous years, Apple is likely to release a half-dozen or more betas, as often as every second week or so, leading up to a Gold Master (GM) seed on or around WWDC 2010 (date yet to be announced) for iPhone and iPod touch, and September for iPad.

Things can and will change. Features will come and go. And all sorts of iOS secrets will be discovered deep inside the code strings. We'll update when any of that happens.

What Hasn't Changed

As always, we'll start off by telling you what hasn't change so we can clear the deck for what has. For more information on any functionality that's pretty much identical to past versions, check out our previous walkthroughs:

YouTube: Accounts were a big addition in iPhone 3.0, so iPhone 4 sits this update out, at least so far.

Stocks: Similarly, Stocks got landscape and a slew of swipe-able data last time, so the update love gets skipped this time.

Weather: Almost comedically at this point, it's still unchanged from iPhone 1.0. Still no HTC TouchFlo 3D style animations, no landscape mode with more/different information. Nada.

Voice Memo: Introduced in iPhone 3.0, it looks pretty much the same in iPhone 4.

Clock: With nothing but a lap feature added last time, we lose the "but" and keep the "nothing" for iPhone 4.

Calculator: Upgraded back in 2.0 for landscape scientific mode, all Calculator gets this time is a slight icon tweak towards the red.

System-wide enhancements

Spell check

Spell check, which debuted in iPhone 3.2 for iPad, is a system-wide addition to iPhone 4 now as well. Words the OS thinks you've misspelled will be underlined in red (familiar to any Microsoft Office or Mac OS X user). Tapping on them will give you a popup containing a recommended replacement. Tapping that replaces the misspelled word with the (hopefully!) correctly spelled one.

Combined with the iPhone's existing -- and industry leading -- predictive auto-correct, it's a powerful combination.

Text Replace

Cut, copy, and paste also gets an iPad-debuting feature with "replace" now added to the popup options.

Bluetooth Keyboard Support

You're going to get tired of us saying "like the iPad" but remember when we told you spring's influx of iPad news would be important come summer's new iPhone news? You were warned for a reason. iPhone is getting iPad's Bluetooth keyboard support. Thank goodness for that.

Home Screen

SpringBoard app, the power behind the Home Screen gets an iPhone 3.2 for iPad-style update to support custom wallpaper. Yes, the default background in iPhone 4 beta 1 is water drops on gray, which is not default but included in the iPad's wallpaper gallery (yet strangely not included in iPhone 4's) Also like iPad, the Mac OS X reflective Dock (buh-bye grid) and translucent top bar have been brought over.

Apple has brought over some of the iPad wallpapers but also introduced a few new ones, all seemingly focused on livening up the home screen without being too visually distracting. Natural textures and muted patterns get an obvious focus here with stones, rocks, and textiles front and center.

In addition to previous status icons, the top bar will now show a north-east pointing arrow to alert you that location-based services (GPS) are being used. (So you'll see this in Maps and when using navigation, location-based social networks or games, etc.)

In addition to the previous color bands across the top of the screen that indicate running voice or data connections (green for Phone, red for Voice Memo, blue for tethering) red is used again to indicate a VoIP app (like Skype) is active in the background.

As mentioned, the Calculator app also gets a new icon. Where things get more exciting is how Home Screen has once again been extended to visualize new, core-level OS changes.

Spotlight

First, and strangely least, the Spotlight Home Screen introduced in iPhone 3.0 now gets to look beyond on-device data and reach for the clouds. Literally. Well, insomuch as the cloud here is Google and Wikipedia, which are very welcome additions. (Hopefully Twitter will be added in as well at some point). Tapping either will launch you into Mobile Safari and the appropriate search result page.

Multitasking

While Apple's built-in apps (like iPod, Mail, etc.) have had background multitasking since 1.0. Now, four years, many gripes, and stiffer Google Android competition than ever, background multitasking comes to App Store apps. At least for the iPhone 3GS and the 4th generation iPhone Apple will more than likely introduce this coming summer. RAM limitations and Apple's abject refusal to put their name on an implementation where hardware constrains software -- see video recording last year -- means iPhone 3G will get a lot of 4.0, but won't get multitasking.

We won't get into the saved-state, streaming music, location, and VoIP APIs, push and local notifications, and task completion that make up the 6 innards of the service because this is a GUI walkthrough. Fast task switching, however, is where we see background multitasking made manifest, and this is what it looks like.

You double tap the Home Screen and the UI turns translucent and slides up, allowing you to peek at the apps running "under the hood". (Technically frozen with state saved an threads registered with those APIs, but we're trying not to get technical here). Positionally the Fast Task Switcher apps take up the space traditionally reserved for the Dock, so while it's a tad confusing the concept of apps at the bottom of the screen being more permanent and easily accessible remains. Behaviorally, while they look like a secret dock, they function like the Home Screen itself in that you can swipe from right to left to scroll through a several 4-icon sets of multitasking apps. We don't know what the upper limit is yet (11 pages like Home Screen itself?) but it's a lot.

Given even the iPhone 3GS has only 256MB of RAM, we assume Apple will discretely kill off the least-used app in the stack when things get tight. Whether or not that means the icon disappears from the multitasking GUI we don't know, but worst case you just have to go to the Home Screen, re-launch it (hopefully from saved state) and all you notice is a slightly longer start up time.

In iOS beta 3, the fast app switcher UI gained a soft-version of the iPad's orientation lock and audio controls. When you double click the home button to bring up the fast app switcher, you can now scroll all the way to the left to get the new orientation lock and audio controls. The default on the orientation is off but a tap will turn on, or turn off, the lock. (Home screen doesn't sound like it rotates, however).

Audio controls include back, play/pause, and forward, with the name of the current track written beneath. If music is being played via the iPod app, the iPod icon will be displayed to quickly get you back to that app. If you're streaming via the iTunes app (i.e. a podcast) then the iTunes icon will be displayed instead. We're guessing iOS will show you the icon of whichever app is currently playing music using the new background audio API, and yes we mean Slacker and Pandora when they're enabled as well.

At the iPhone 4 event, Steve Jobs likened task managers (in the multitasking, not to-do sense) to styluses -- if you need them there's something wrong. However, if you hold your finger down on multitasking apps to make the jiggle and bring up a delete icon that, if you tap it, removes them. Added to the list of things we don't know -- whether that kills their API thread or merely removes them from the Fast App Switcher interface. (And no, sadly you can't re-arrange jiggling apps for fast switching, at least not yet -- if you want your favorites close at hand, that remains a Dock thing).

The background for the app switcher (and for folders) has also changed from the rubbery, pock-mocked, dark gray of beta 1 and 2 to a new cross-hatched medium gray in beta 3.

The presentation may not be as visually slick as Palm webOS' Card view (which looks like iPhone Safari's Page view) or Mac OS X Exposé mode, but it keeps those 85,000,000 existing iPhone and iPod touch users grounded in the interface they're familiar with and that's what Apple is prioritizing.

Note: Previously you could assign the double-click Home to trigger Phone Favorites, Camera, or Spotlight. On iPhone 3G under iOS those options remain. On iPhone 3GS under iOS, you can now double-click-and-hold on Home to trigger Phone Favorites, but there doesn't appear to be any mechanism to re-assign that functionality to Camera or Spotlight (see Settings, below). [@oliok] This appears to be gone under Beta 3.

iOS beta 2 introduced a new, circling, side-switching animation for multitasking fast app switching. The new animation occurs when you switch between two apps either via the new, double-click-Home to trigger to launch the multitasking UI, or when one app calls another app (i.e. when you're in Contacts and you tap to send a contact an SMS).

Launching or leaving an app retains the same, zoom-based effect as always (though the wallpaper in iOS zooms slightly as well, like on the iPad).

Folders

There are 180,000 apps in the App Store and likely a ton more by the time I finish writing the sentence. Literally. iPhone 1.0 had one Home Screen but with only the built-in apps available back then, it wasn't even a limitation. With WebApps, it grew to 9 pages for a 148 app limit. With iPhone 3.0 we were given 8 pages, for 180 apps viewable, but you could install many more and use Spotlight as a way of finding and launching them. Organizing them still wasn't a real option.

Enter Folders. A Folder is simply a grouped icon that holds up to 12 other icons inside it. (And for those keeping count at home, the new math means a whopping 2016 apps can be kept on-screen at once. Shudder).

The way it works is you tap a Folder icon and once again the Home Screen fades and splits open, this time below the Folder. Inside the split are all the apps contained in the group.

To create a Folder, you begin by tapping and holding an icon to put it in jiggly mode, just like you did before to delete or move it. Then, drag it over and drop it on top of another icon to create a Folder. (This works better when icons aren't at the right edge of the screen, as the move behavior seems to supersede the Folder behavior, causing the icon to wrap to the next line before you can drop on top of it.) Once created, iPhone OS reads the apps' category data and tries to name the folder for you, but you can easily edit it to anything you want.

To remove apps from a Folder, put them in jiggly mode inside the Folder and drag them out (or just delete them if you don't want them anywhere anymore). You can also move them around within the Folder to customize their order.

Folders can be put in jiggly mode and moved as well, but not deleted (they can only be deleted by removing all the apps from within them, and which point they self-destruct for you). You can even move them to the Dock, which means you could have 48 apps readily available at any time for quick launching.

And while you still can't delete Apple's built-in apps, you can take the ones you're not using and hide them away inside a folder so they waste as little Home Screen space as possible (not that that's as big a deal now as it used to be...)

Again, not as visually exciting perhaps as Mac OS X's Stacks, but it keeps current iPhone users in a familiar interface while adding much-needed functionality.

Messages

Messages in iPhone 4 gets the same built-in Spotlight search that Mail and other apps got with iPhone 3.0. It appears at the top of the main messages screen. (There's no search within an individual Messages thread). [@justin_horn]

Messages also (finally) gets a character counter so you'll know when you're getting close to, or going past, the SMS limit (which would cause a second message to be sent). It kicks in after you've typed 50 characters or so. [@iMuggle]

There's also a new API to allow in-app SMS for developers who want to include the functionality in their own apps. While this might be similar to the iPhone 3.0 embedded email option, and whether or not it will let users reply to SMS without leaving an app, it doesn't seem as elegant a solution as a global background messaging system.

Calendar

Calendar removes two long-standing gripes and adds something pretty much invisible from the interface but awesome in terms of functionality.

First, you can now show all or hide all calendars or individually check/uncheck just the calendars you want to see.

Birthday calendars have also been added to the option, something that was previously only possible to see under certain setup conditions.

Lastly and most excitingly, Apple has finally added Calendar access for developers. What this means is, we'll soon see applications where, by way of example, you can download a movie app, buy tickets for a local screening, and the app will be able to automatically add the show time to your Calendar.

Photos

Photos, at least for Mac users, gets the same iPhoto '09-based organizational features introduced with the iPad: Events, Faces, and Places.

If you have a Mac with iPhoto '09 and you've let it automatically file your photos by time stamp (Events), through facial-recognition algorithms (Faces), and via geo-location (Places). All these join the previous Albums view to form the bottom tab bar.

Landscape mode is also now supported in album and gallery views [@antonioj].

The action button now includes a Rotate function (yes!) that turns a photo 90 degrees counter-clockwise (to the left).

If you Email Photo, you now get the option of sending a smaller version (compressed dimensions and hence file size), or at actual size.

Lastly, developers have been given access to the photo and video library (not just the image picker as in previous OS versions).

Camera

Tap to focus, introduced in iPhone 3.0 for still photography, now gets expanded to video recording for the iPhone 3GS (and presumably the 4th generation iPhone).

Still photography maintains its leg up, however, via a new 5x digital zoom. When you tap the screen, a slider pops up allowing you to swipe to the right to increase magnification and swipe left to decrease.

Developers also get full access to and control of video playback and recording.

Maps

A minor tweak, but the current location/current direction button changes from the previous crosshairs to a north-east pointer to match the new location services icon used in the title bar. (No iPhone 3.2 for iPad-style terrain mode, at least not yet).

For developers, overlays can now be added to embedded maps to show extra data like routes or annotations.

Notes

When you first enter notes it looks unchanged from previous versions of the iPhone OS. However, there is now an Accounts button at the top left of the list page and tapping it takes you to a new screen where you can choose to view All Notes, just the notes on your iPhone, or just the notes that are synced via IMAP to your email account(s). Yes, that means over the air (OTA) notes sync is finally here -- with the caveat that Exchange doesn't seem supported yet.

(UI-wise this is similar to how you back out/left in Calendar or Contacts to toggle data sources.)

The way these show up in Mac OS X is via the built-in Mail.app client in the Notes tab.

On Gmail they show up as a generic label. In other IMAP clients, regardless of OS, they'll show up as generic IMAP folders.

iTunes Store

The iTunes store itself is the same, however, audio streaming from the app itself has taken a huge leap forward. Since iPhone OS 2.2 you've been able to tap the title of a podcast to begin streaming (rather than downloading) the audio, even in the background while using other apps, but it was sometimes hit or miss. It would drop out, it would time out, you couldn't really scrub through it, and if you left it for a while it would lose its place and start over.

In iOS it's rock solid. You can scrub and it re-buffers and keeps playing flawlessly. You can stop it and come back hours or even days later -- even after using the iTunes app to search for other things or the iPod app to play different audio -- and it still knows where you left off and starts playing again instantly without missing a beat.

Settings

This year, like every year, some of the more numerous and interesting changes Apple delivers in their new OS are tucked neatly away in the Settings app.

General: Network

You can now choose to not only turn off 3G data or roaming data, but all cellular data.

General: Location Services

At the iOS event, Apple made a big deal about user privacy when it came to location (like a shot at Google). That manifests here with far more granular controls over which apps are allowed to access your location data (GPS, Wi-Fi mapping, and cell tower triangulation) and the aforementioned north-east pointing arrow that shows up when any app has used your location in the last 24 hours.

General: Home Button

Rather than gaining functions, the Home Button setting loses several. Since double-click for iOS on the iPhone 3GS (and presumably future iPhone hardware) is now reserved for launching the multitasking interface, gone is the option to assign it to launch Spotlight, Camera, or iPod. Also gone is the option to have it launch iPod when audio is playing.

Double-click-and-hold will now trigger Phone Favorites on the iPhone 3GS, but no options are presented yet to re-assign that to Spotlight, Camera, or iPod. So, the only thing that remains are the Spotlight search inclusion options. Looks downright barren now...

General: Passcode Lock

Previously available only through an Enterprise profile, iPhone 4 brings stronger, alphanumeric passcodes to all iPhone users. That means you're no longer stuck with only a 4 digit pin, but can now create longer passcodes with far greater variation. Of course, longer, more varied passcodes are more of a hassle to remember and enter, but that's the cost of good security.

Mail, Contacts, Calendars

As previously mentioned, Notes will now sync over IMAP and the settings for that appear here. First, all the way at the bottom, you can choose which account to use as the default for note sync.

Inside MobileMe, Gmail, or other IMAP accounts, you can choose whether or not to enable sync. Again, there's no support for Exchange ActiveSync accounts yet (including Gmail via GoogleSync).

Messages

Here's where you can turn on that new character count option.

iPod

The iPod app now has an overlay that shows you information about songs and podcasts. While functional it's not terribly attractive so it's nice to be able to toggle it off right here.

App Store

iAd

iAd will provide developers with an easy-as-Xcode way to place advertising in their apps, both paid and free. Apple is setting a high bar for their ads, however. No simple Google-style text, annoying punch-the-monkey, or jarring transition out of the app and into the browser, they claim to want great looking, highly interactive, emotionally compelling content that will connect with rather than alienate users. Served every 3 minutes. Yeah...

Functionally these are built in HTML5 (no Flash need apply) and seem to work as apps-within-apps. Tapping on a banner brings up a full-screen ad-as-webapp and examples shown included plenty of animated UI effects and content that ranged from videos to freebies like wallpaper, to free and paid apps you could download from within the ad (no trip to the App Store needed). An exit button is persistent at the top left so users can quit the add at any time.

Apple will be selling and serving the ads, so all we can do is hope they're unobtrusive and actually reach the quality levels presented. For paid apps that also try to include in-app iAds, that bar will rightly be very, very high.

Task completion

With iPhone 4, when you close and app and that app is still performing an activity, the OS will allow it to complete that activity in the background. For example, downloading or uploading content from the internet.

Streaming music, location, and VoIP API

The underside of the multitasking/fast app switching UI mentioned at the beginning of the walkthrough are three specific types of API that an app can register threads with when you close them out. These are intended for streaming music (Pandora or Slacker being the classic examples), location-aware (i.e turn-by-turn navigation, check-in games, social networks, etc.), and VoIP (Skype and SIP clients) to register with the OS when you exit the apps proper so that your music can keep streaming, location can keep tracking, and VoIP can still alert you of phone calls even when the app isn't running.

There's no time-line API for instant messaging (IM), Twitter, etc. to register their threads with, however. Apple believes existing Push Notifications are sufficient but that means once an alert is received and you tap View, the app still has to pause and load the timeline/messages before you can view them. This is unlike the built-in Mail and Messages (SMS/MMS) apps that have new messages loaded and waiting when you get there.

Local Notifications

Like Push Notifications in iPhone 3.0 but not requiring an outside, internet connected server, local notifications will let apps you're using (and perhaps apps that have registered one of the three types of background threads mentioned above) send you popup boxes, sound alerts, and icon badges.

For the user, these should be functionally the same and perhaps indistinguishable.

Quick Look

Just like Mail can preview documents, Quick Look will allow developers to present the same functionality in their apps.

Accelerate

2000 hardware accelerated math APIs probably won't be seen by users, but there's not doubt we'll feel them in the games. Zoom. Zoom.

File Sharing

Again it looks like the iPhone is finally getting in iOS what the iPad got in 3.2 with the file/document transfer feature now exposed in iTunes sync.

While the iPad version identifies document-friendly apps (like Apple's own Keynote, Numbers, and Pages) and lets you find and sync over files, the iOS beta 3 version currently only shows Mail and Stanza and doesn't really let you do much else. However, it stands to reason this will at least reach feature parity with the iPad when Apple releases iOS to the public later this summer.

Now all we need is an elegant way to share and wirelessly sync those documents across multiple devices and users. MobileMe 2.0, souped up iWork.com 2.0, where are you?

Mail

Mail gets a unified inbox. Let's write that again -- Mail gets a unified inbox. For those with multiple email accounts whose previous iPhone experience involved tapping into and out of those boxes many, many times a day this is a hugely welcome addition.

As with Calendars, Notes, etc. you can tap a button on the top left, in this case Mailboxes, to back into a selection screen where you can then go into All Inboxes, a specific account's inbox (which is considered fast inbox switching), or into the complete folder and sub-folder system of a given account (how Mail has worked from iPhone 1.0 to iPhone 3.0).

Once inside, All Inboxes is visually indistinguishable from an account-specific inbox, it simply contains all of their messages.

What is distinguishable are the small carets (technically greater-than symbols) to the right of replies that indicate a message is part of a thread. A number, typically 2 or 3, accompanies the caret to indicate how many replies are in the thread.

Tapping on a message that's part of a thread doesn't take you to the message but rather to a second list-view, similar to the inbox itself, but containing only the messages from the thread. Tapping on one of them then takes you to the message.
A thread view contains a small vertical bar at the top with the subject of the thread and time of the most recent reply. A button to the top left of the message that's part of the thread also contains the subject of the thread and lets you back out and see the thread again. The button then switches to contain the name of the inbox so you can back out again, leave the thread completely, and see all your messages.

So yes, the tap, tap, tap of inbox navigation persists, albeit shifted from moving into and out of inboxes to moving into and out of threaded messages.

Although not yet implemented in the current beta, like iPhone OS 3.2 for iPad, you'll be able to open email attachments in apps. Now there's no iWork (Numbers, Pages, Keynote) for iPhone yet, and the app Apple used to introduce this function doesn't exist on iPhone yet either. Interesting.

Lastly, in previous versions of the iPhone OS, when you wanted to abandon an email, you would hit Cancel and get options to Save (store the email in Drafts), Don't Save (trash the email), and Cancel (go back to writing the email). The naming of these options was likely too confusing so in iPhone OS they've been replaced with a big red Delete button (to trash the email), Save as Draft, and Cancel. And yes, you can still cancel a cancel. (iPad, by contrast, still has Save and Don't Save, but no Cancel since it's in a popover rather than full-screen menu and you can just tap away to cancel).

Safari

More iPad to iPhone cross-polination means we get search auto-complete from both Google and Yahoo! in iOS. As you type, suggestions appear in a list view below. And as with the iPad, while Google and Yahoo! branding remain in the search boxes, they no longer get brand advertising on the keyboard -- it simply remains labeled Search now regardless of which engine is set and default.

As usual, Apple seems to be increasing Safari's HTML5 support. While HTML5 video would work under iPhone 3.1.3, it would launch the full screen QuickTime player to do so. Under iOS, it seems to play in-line as well [MobileGeekdom], like it does on the iPad.

If history is any indicator, Apple will likely also integrate whatever advancements WebKit and the Nitro JavaScript engine make between now and release this summer.

iPod

When you have a song playing in the iPod app and you tap the album art, in addition to all the previous controls that popped up, you now get a dark overlay with white text giving you the info metadata of the song or podcast. This is another iPad bring-over, though not the most attractive one by a long shot. (Remember, it can be turned off in Settings).

Album art has been added to album views, jazzing up the track lists. [Gizmodo]

And in yet another iPad-like update, on-th-go playlists are dead, long live... just regular old playlists. You can add them via an item in the playlists list, at which point you get a popup that asks you for a name. Next, you tap on any songs you want to add, and when you're done, you have a new playlist. If you're not happy with it, or any playlist, just swipe to bring up the usual red Delete button and annihilate it.

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Nike+

You can now send you run data directly from the iPhone. [When Will Apple]. Under History, tap Send to Nike+ and you're off and running (sorry). You're then sent to Safari so you can login to Nike+ and see your data.

Game Center (Preview)

Game Center is Apple's entry into the social gaming network space (think Xbox Live or Playstation Network for iPhone OS devices). With Game Center you'll be able to invite friends to play, use matchmaking to challenge other players, gain achievements, and have your scores displayed on a leader board.

Game Center won't launch with iOS this summer, but is scheduled for release "later" this year.

iBooks

Though not a built-in app (you'll need to go get it from the US App Store when it becomes available), as part of iOS Apple announced they were bringing iBooks to the iPhone.

Not Concluded

This preview won't be concluded until Apple concludes iOS with its final release this summer for iPhone and iPod touch, and this fall for iPad (unless that becomes iPhone 4.1).

iPhone 3G and iPhone 3GS owners should get it for free as Apple's 2-year accounting procedure allows. That there's been no word about iPhone 2G owners could mean it's either not going to be available for the oldest hardware, it won't be free, or... there's simply been no word yet. Likewise, there's been no word on iPod touch pricing though it was $9.95 for iPhone 3.0. There's been no word on iPod touch G1 availability either, however. Apple's SDK agreement has revealed that iPad users who bought with 3.2 will get 4.0 for free but not subsequent major updates (i.e. iPhone OS 5 in 2011).

Again, there will be roughly 6 to 8 betas released on a roughly bi-weekly schedule from now until WWDC 2010 when we'll likely hear about the final version, whatever extra features will come with the next-generation iPhone (current rumors suggest iChat video), and get a final release data -- likely also to coincide with the next-gen iPhone release date.

We'll update this preview as more and better information becomes available, so if you notice anything we missed or just plain got wrong, send it in or let us know in the comments.

Note on Using Beta Software

If you're not a developer, don't even think about putting iOS beta on your main iPhone. Betas are for testing purposes and could contain any number of bugs and performance issues, could stop working or require updates when you may not have access to one, or otherwise give you problems when used in a manner for which they're not intended. Stay away.

[Thanks to everyone who contributed screenshots and descriptions for this walkthrough]

nice review, i've decided to wait til beta 2 to install it on my phone, that's what I did with 3.0 and it ran fine, I love my new mac tho, never thought I'd say it but I like it more than my pc, it's like 1/20 the size too

Quality preview. I am hoping that they will extend the double-click and hold for the options they took away while implementing limited multitasking. One question though, when was iPhone OS 3.3 released since it's stated in the safari preview section?

@ghostface147: You mean 3.1.3, right? 3.3 wasn't released yet (and will likely never be); 3.1.3 is out since a few weeks, even months now.
I have one question: The way I see the new multitasking functionality - doesn't it always clutter the new "multitasking dock" immediately as soon as you start using e few apps (that are MT-enabled)? This means that it gets quite troublesome to use quite fast, right? And this also means that the feature to remove apps from MT (the task-manager substitute that Steve Jobs talked down) will be used rather frequently? Or is there a way to easily quit an app the way it quits on OS 3 when the home button is pressed, like pressing it longer or something? Or am I missing something? Thanks!

Sounds great.
But really, a unified in box? Are people REALLY excited about this? Seriously, I have 6 email accounts. If the worst part of my day is that I have to press the back button twice to get to my mail box view, then I must have a pretty comfortable life.
I don't get why people act like this is a lot of work.

What about features like specific alerts? Different number of pulses for text messages or emails? Or specific sounds for important emails? To get further into the enterprise it seems like these features need to be incorporated to cover BB.

"iPhone 3G and iPhone 3GS owners should get it for free as Apple’s 2-year accounting procedure allows."
If I'm reading this right, then I have less than one year until I have pay for my next upgrade for my 3GS?

Great post. On multitasking though I think you misunderstood the keynote. The debs can use apples built in services. The app itself is not staying open. It's just saved state. Ram really is not much of an issue in this regard because none of the apps are actually open.

Awesomely stated review. I absolutely live for reading a post like this. No joke. It was amazing. It was so simply put, I felt like I was reading 'Whinnie the Pooh' on an iPad!
Hopefully I'll be getting the next iPhone when my contract expires in the fall.

P.S. -- If there were actually blueprints for an iPhone OS like Apple shows for their little 'iPhone 4' website and the photo used here, I would totally pay $100 to see them... :) (...drifts to sleep in a iPhone-Fanboy-esque way)

Mail:
I use an IMAP account with server based rules that would sort mt incoming mail into subfolders. I found it always a bit annoying on the iPhone that I would have to open each folder individually just to know the number if unread mails in it. Some kind of "refresh all" button would be highly apprechiated.
Anyone knows if there's a change about that in OS 4?

Regarding Rene's comment that multitasking will come with OS 4, "...At least for the iPhone 3GS and the 4th generation iPhone Apple will more than likely introduce this coming summer.", remember that the latest iPod touch will also get iPhone OS 4.

Excellent. I'm just disappointed in apple taking away the iPod shortcut. The main reason why I own an iPhone is for the iTunes integration and how easy it was to access music... now that's sorta messed up.
One thing I noticed is the task completion. That's absolutely nothing new. It's almost on the same level as multitasking. The phone could multitasking before but for only native apps. The iTunes store and mail could task complete since the day they put it on the phone.
Steve tried to make having a background on the home screen look like it was something cool. Psh. Get over ur self Steven. People have been doing that for a while now.
At the end of the day I'm not excited so far but I'm satisfied.

Does anyone have an answer to Parabel's question:
"I have one question: The way I see the new multitasking functionality – doesn’t it always clutter the new “multitasking dock” immediately as soon as you start using e few apps (that are MT-enabled)? This means that it gets quite troublesome to use quite fast, right? And this also means that the feature to remove apps from MT (the task-manager substitute that Steve Jobs talked down) will be used rather frequently? Or is there a way to easily quit an app the way it quits on OS 3 when the home button is pressed, like pressing it longer or something? Or am I missing something? Thanks!"
I agree. it becomes a mess. Instead of using your normal menu you'd be scrolling left and right to find an app. you might as well just use springboard to launch your app rather than the task manager?

the best thing aboutthis is thatiphone has survived and is now on top. i bet that sooner or later it will beat software giant microsoft. since 1999 aple has changes and always come up with new ideas. divz

Two more questions
Is mail threading proper threading by reference, or just lame GMail-like subject matching?
For playlists are you still stuck with building them in one go or can you add to them later?

Theoretically the new MT dock quietly kills off stuff before it becomes problematic the way the OS already does for inbuilt apps when it needs to reclaim memory - If you are witted about too many apps to scroll through- maybe there were better ways to do this visually, but are you really complaining about getting what one of the things we've all been demanding for years?

I really think this is going to be a very solid update. I just hope that within those other 93 other features some alleviate the excess back and forth tapping to get to settings. Some drop down screens or at the very least one is absolutely necessary. This should be the ease of use update.

one gripe a friend of mine has is that the iPhone still does not have the ability to assign a custom SMS ringtone on a per-Contact basis, like you can do on almost every other phone on the planet.
any word on that working in OS4?

So you want a passcode to unlock the phone (which will now allow alphanumeric unlocks) and another passcode to unlock each area that may contain personal info? To each their own, I guess; sounds like a giant p.i.t.a to me.

The images aren't cropped, those are just the default thumbnail view. Click on them and they should automatically expand to the full image. Sorry if it's causing confusion.
Added more on Messages and iPod.

Echoing Q 54. The short list of default sounds/tones available on the iPhone should be embarrassing to Apple. And assigning different tones to different contacts isn't rocket science.
Will they open this up?

@jonar1us - don't be a jackass, and set aside your strawman for a moment. I never said that a) I wanted variable message tones or that b) that those were more important than security or c) that I didn't want other people to have the option if they wanted.. It is just not something that I would use as anything private on my iPhone is stored in 1Password and similar apps that also have lock codes.

@Mike: I just subscribe the calendars using their individual CalDAV adresses. You'll need the calendar ID that is being displayed in the calendar options in Google, ending with @group.calendar.google.com
Go to Mail and Calendar, add account, choose other, then CalDAV. Enter www.google.com for server and username and password. Then choose next. Depending on your calendar setup, you might need to re-open the calendar settings, go to advanced settings and changing the URL. You would then have to exchange the part between ...dav/ and /user with your calendar ID, but this usually only applies if you use more than one calendar per account...
HTH

Yes I can see the images in full size if I click on them, but in a new tab or replacing the article - which takes them out of context. Happens in Safari, Firefox, Chrome and Mobile Safari. I don't even see the point of 'thumbnailing' them. It's an enormously long page as it is. The graphics are very important to the article and should be fully viewable inline.

@Allister I see the same thing, opens a page just for the image and then when I click back I have to find my place again. I know for sure they use to have a lightbox type popup for images, maybe something got messed up?

Do you think multitasking means that we will finally be able to get call recorder on our iPhone? As a reporter, this would be of a great support. And don't tell me about the law concern, here in Quebec, it's not prohibited...

It would be nice if in the calendar there would be a "Snooze" option for reminders. Right now there is only Dismiss or View Event.
Windows Mobile a decade ago had a Cut Copy & Paste option with an appointment in the Calendar by clicking down on the appointment and selecting Cut and the you could pick the slot you wanted to put it in and paste it in directly. The iPhone requires up to 13 steps to make a change to an appointment.
Also would be nice to have an ignore button pop up on a call to send the person to voicemail. the only time the "Ignore" option comes up is when I am already on a call.

Is anyone else really hoping for an update to google maps? After having an android phone google maps is really starting to seem out of date on the iPhone. I really want the free turn by turn navigation!

@Zeagus
I know this is way late but having a lock feature on specific apps such as MMS, Email, or whatever you didn't want someone to access. I know the Passcode lock is great but if my niece wants to play on my phone like she often does then I can sleep soundly knowing that she won't read any text above her age or see any emails she shouldn't. Let's not forget snooping girlfriends and buddies. She asks to see your phone to play Bejeweled 2 and the next thing she's asking you what you meant in a joke text to your friend she hates. It would be a MUCH welcome feature.

@Rick. I know how you feel. I recently got rid of my Nexus One to come back to the iPhone 3GS (since I'm not eligible till 8/2011). Anyway, free turn by turn would be great but I can't see AT&T allowing it while they offer Telenav - and add to the fact that the iPhone is their flagship device. sigh

I'd also like to mark appointments as private but, more, I want to be able to copy an appointment to a new date. At present, I can change its date, but then I've lost the record of the original appointment. (This is not the same as recurring appointments.)